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THURSDAY, April 26, 2012 — One look at Olympic weight-lifters shows that the heavier the weights, the stronger the weight lift, right? Although there's definitely some truth to this conventional workout wisdom, a new position paper published in the journal Applied Physiology, Nutrition, and Metabolism argues that there's more to the story.

Weight training with less weight but more repetition may be as effective for building muscle as lifting heavier weights for fewer repetitions, said researchers at McMaster University in Ontario. The key to muscle gain, researchers say, is working the muscles to the point of fatigue, no matter the weight size. They want you to feel the burn.

The authors of the paper conducted a series of experiments to measure how muscles react to different forms of training. They found, not surprisingly, that high-intensity muscle contractions from lifting heavy weights produced muscle development. But when volunteers performed resistance training with smaller weights until they reached muscle fatigue, identical muscle development was formed. The higher repetitions also helped sustain the muscle-building response in the days following the workout.

This means you can continue using 3-pound hand weights for bicep curls if you want. But if you want to see a bigger, stronger bicep, you must keep up the curls until you have to fight to pull up the weight each time. (For a woman who works out regularly, this could means scores of repetitions.)

No matter how you chose to get there, the key to seeing a real benefit from strength training is using enough weight to challenge yourself, and repeating the exercises enough times that your muscles reach fatigue. As you get stronger, remember to switch to progressively heavier weights to keep on feeling the burn.

Why Strength Training is Essential

Now that you know how to strength train to build muscle mass, here's why strength training should be a regular part of your fitness routine.

Increasing muscle mass is the only way to boost metabolism. Fad diets claim they can increase your metabolism, but the only real way to make it happen permanently is to increase your muscle mass. This is because muscle burns more calories than fat, even at rest.

Regular weight training can help protect your brain. As you age, strength training can help keep you sharp. One recent study found that women who started strength training at the first signs of memory decline might ward off full-blown dementia by routinely lifting weights.

Strength training plays a role in bone and joint help. One of the best ways to prevent or even reverse bone density loss is through strength training. If you have arthritis, studies have shown that regular resistance training can help ease joint pain.

Lean muscle looks good. Last but certainly not least, weight training is a surefire way to build those long, lean muscles so many women want. If you're worried that weight training will make you look bulky, know that women do not have the testosterone levels required to get bigger from weight lifting. Instead, you'll look lean and toned.